本文转自：http://www.cnblogs.com/Leo_wl/p/6077203.html

注：本文提到的代码示例下载地址> How to achieve a bearer token authentication and authorization in ASP.NET Core

在ASP.NET Core中实现一个Token base的身份认证

以前在web端的身份认证都是基于Cookie | Session的身份认证, 在没有更多的终端出现之前，这样做也没有什么问题， 但在Web API时代，你所需要面对的就不止是浏览器了，还有各种客户端，这样就有了一个问题，这些客户端是不知道cookie是什么鬼的。 (cookie其实是浏览器搞出来的小猫腻，用来保持会话的，但HTTP本身是无状态的, 各种客户端能提供的无非也就是HTTP操作的API)

而基于Token的身份认证就是应对这种变化而生的，它更开放，安全性也更高。

基于Token的身份认证有很多种实现方式，但我们这里只使用微软提供的API。

接下来的例子将带领大家完成一个使用微软JwtSecurityTokenHandler完成一个基于beare token的身份认证。

注意：这种文章属于Step by step教程，跟着做才不至于看晕，下载完整代码分析代码结构才有意义。

前期准备

创建项目

在VS中新建项目，项目类型选择ASP.NET Core Web Application(.NET Core), 输入项目名称为CSTokenBaseAuth

Coding

  • 创建一些辅助类

    在项目根目录下创建一个文件夹Auth,并添加RSAKeyHelper.cs以及TokenAuthOption.cs两个文件

    • 在RSAKeyHelper.cs中

      1. using System.Security.Cryptography;
      2.  
      3. namespace CSTokenBaseAuth.Auth
      4. {
      5.     public class RSAKeyHelper
      6.     {
      7.         public static RSAParameters GenerateKey()
      8.         {
      9.             using (var key = new RSACryptoServiceProvider(2048))
      10.             {
      11.                 return key.ExportParameters(true);
      12.             }
      13.         }
      14.     }
      15. }

    • 在TokenAuthOption.cs中

      1. using System;
      2. using Microsoft.IdentityModel.Tokens;
      3.  
      4. namespace CSTokenBaseAuth.Auth
      5. {
      6.     public class TokenAuthOption
      7.     {
      8.         public static string Audience { get; } = "ExampleAudience";
      9.         public static string Issuer { get; } = "ExampleIssuer";
      10.         public static RsaSecurityKey Key { get; } = new RsaSecurityKey(RSAKeyHelper.GenerateKey());
      11.         public static SigningCredentials SigningCredentials { get; } = new SigningCredentials(Key, SecurityAlgorithms.RsaSha256Signature);
      12.  
      13.         public static TimeSpan ExpiresSpan { get; } = TimeSpan.FromMinutes(20);
      14.     }
      15. }

  • Startup.cs

    在ConfigureServices中添加如下代码：

    1. services.AddAuthorization(auth =>
    2. {
    3.     auth.AddPolicy("Bearer", new AuthorizationPolicyBuilder()
    4.         .AddAuthenticationSchemes(JwtBearerDefaults.AuthenticationScheme‌​)
    5.         .RequireAuthenticatedUser().Build());
    6. });

    完整的代码应该是这样

    1. public void ConfigureServices(IServiceCollection services)
    2. {
    3.     // Add framework services.
    4.     services.AddApplicationInsightsTelemetry(Configuration);
    5.     // Enable the use of an [Authorize("Bearer")] attribute on methods and classes to protect.
    6.     services.AddAuthorization(auth =>
    7.     {
    8.         auth.AddPolicy("Bearer", new AuthorizationPolicyBuilder()
    9.             .AddAuthenticationSchemes(JwtBearerDefaults.AuthenticationScheme‌​)
    10.             .RequireAuthenticatedUser().Build());
    11.     });
    12.     services.AddMvc();
    13. }

    在Configure方法中添加如下代码

    1. app.UseExceptionHandler(appBuilder => {
    2.     appBuilder.Use(async (context, next) => {
    3.         var error = context.Features[typeof(IExceptionHandlerFeature)] as IExceptionHandlerFeature;
    4.         //when authorization has failed, should retrun a json message to client
    5.         if (error != null && error.Error is SecurityTokenExpiredException)
    6.         {
    7.             context.Response.StatusCode = 401;
    8.             context.Response.ContentType = "application/json";
    9.             await context.Response.WriteAsync(JsonConvert.SerializeObject(
    10.                 new { authenticated = false, tokenExpired = true }
    11.             ));
    12.         }
    13.         //when orther error, retrun a error message json to client
    14.         else if (error != null && error.Error != null)
    15.         {
    16.             context.Response.StatusCode = 500;
    17.             context.Response.ContentType = "application/json";
    18.             await context.Response.WriteAsync(JsonConvert.SerializeObject(
    19.                 new { success = false, error = error.Error.Message }
    20.             ));
    21.         }
    22.         //when no error, do next.
    23.         else await next();
    24.     });
    25. });

    这段代码主要是Handle Error用的，比如当身份认证失败的时候会抛出异常，而这里就是处理这个异常的。

    接下来在相同的方法中添加如下代码，

    1. app.UseExceptionHandler(appBuilder => {
    2.     appBuilder.Use(async (context, next) => {
    3.         var error = context.Features[typeof(IExceptionHandlerFeature)] as IExceptionHandlerFeature;
    4.  
    5.         //when authorization has failed, should retrun a json message to client
    6.         if (error != null && error.Error is SecurityTokenExpiredException)
    7.         {
    8.             context.Response.StatusCode = 401;
    9.             context.Response.ContentType = "application/json";
    10.  
    11.             await context.Response.WriteAsync(JsonConvert.SerializeObject(
    12.                 new { authenticated = false, tokenExpired = true }
    13.             ));
    14.         }
    15.         //when orther error, retrun a error message json to client
    16.         else if (error != null && error.Error != null)
    17.         {
    18.             context.Response.StatusCode = 500;
    19.             context.Response.ContentType = "application/json";
    20.             await context.Response.WriteAsync(JsonConvert.SerializeObject(
    21.                 new { success = false, error = error.Error.Message }
    22.             ));
    23.         }
    24.         //when no error, do next.
    25.         else await next();
    26.     });
    27. });

    应用JwtBearerAuthentication

    1. app.UseJwtBearerAuthentication(new JwtBearerOptions {
    2.     TokenValidationParameters = new TokenValidationParameters {
    3.         IssuerSigningKey = TokenAuthOption.Key,
    4.         ValidAudience = TokenAuthOption.Audience,
    5.         ValidIssuer = TokenAuthOption.Issuer,
    6.         ValidateIssuerSigningKey = true,
    7.         ValidateLifetime = true,
    8.         ClockSkew = TimeSpan.FromMinutes(0)
    9.     }
    10. });

    完整的代码应该是这样

    1. using System;
    2. using Microsoft.AspNetCore.Builder;
    3. using Microsoft.AspNetCore.Hosting;
    4. using Microsoft.Extensions.Configuration;
    5. using Microsoft.Extensions.DependencyInjection;
    6. using Microsoft.Extensions.Logging;
    7. using Microsoft.AspNetCore.Authorization;
    8. using Microsoft.AspNetCore.Authentication.JwtBearer;
    9. using CSTokenBaseAuth.Auth;
    10. using Microsoft.AspNetCore.Diagnostics;
    11. using Microsoft.IdentityModel.Tokens;
    12. using Microsoft.AspNetCore.Http;
    13. using Newtonsoft.Json;
    14.  
    15. namespace CSTokenBaseAuth
    16. {
    17.     public class Startup
    18.     {
    19.         public Startup(IHostingEnvironment env)
    20.         {
    21.             var builder = new ConfigurationBuilder()
    22.                 .SetBasePath(env.ContentRootPath)
    23.                 .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
    24.                 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);
    25.  
    26.             if (env.IsEnvironment("Development"))
    27.             {
    28.                 // This will push telemetry data through Application Insights pipeline faster, allowing you to view results immediately.
    29.                 builder.AddApplicationInsightsSettings(developerMode: true);
    30.             }
    31.  
    32.             builder.AddEnvironmentVariables();
    33.             Configuration = builder.Build();
    34.         }
    35.  
    36.         public IConfigurationRoot Configuration { get; }
    37.  
    38.         // This method gets called by the runtime. Use this method to add services to the container
    39.         public void ConfigureServices(IServiceCollection services)
    40.         {
    41.             // Add framework services.
    42.             services.AddApplicationInsightsTelemetry(Configuration);
    43.  
    44.             // Enable the use of an [Authorize("Bearer")] attribute on methods and classes to protect.
    45.             services.AddAuthorization(auth =>
    46.             {
    47.                 auth.AddPolicy("Bearer", new AuthorizationPolicyBuilder()
    48.                     .AddAuthenticationSchemes(JwtBearerDefaults.AuthenticationScheme‌​)
    49.                     .RequireAuthenticatedUser().Build());
    50.             });
    51.  
    52.             services.AddMvc();
    53.         }
    54.  
    55.         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline
    56.         public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    57.         {
    58.             loggerFactory.AddConsole(Configuration.GetSection("Logging"));
    59.             loggerFactory.AddDebug();
    60.  
    61.             app.UseApplicationInsightsRequestTelemetry();
    62.  
    63.             app.UseApplicationInsightsExceptionTelemetry();
    64.  
    65.             #region Handle Exception
    66.             app.UseExceptionHandler(appBuilder => {
    67.                 appBuilder.Use(async (context, next) => {
    68.                     var error = context.Features[typeof(IExceptionHandlerFeature)] as IExceptionHandlerFeature;
    69.  
    70.                     //when authorization has failed, should retrun a json message to client
    71.                     if (error != null && error.Error is SecurityTokenExpiredException)
    72.                     {
    73.                         context.Response.StatusCode = 401;
    74.                         context.Response.ContentType = "application/json";
    75.  
    76.                         await context.Response.WriteAsync(JsonConvert.SerializeObject(
    77.                             new { authenticated = false, tokenExpired = true }
    78.                         ));
    79.                     }
    80.                     //when orther error, retrun a error message json to client
    81.                     else if (error != null && error.Error != null)
    82.                     {
    83.                         context.Response.StatusCode = 500;
    84.                         context.Response.ContentType = "application/json";
    85.                         await context.Response.WriteAsync(JsonConvert.SerializeObject(
    86.                             new { success = false, error = error.Error.Message }
    87.                         ));
    88.                     }
    89.                     //when no error, do next.
    90.                     else await next();
    91.                 });
    92.             });
    93.             #endregion
    94.  
    95.             #region UseJwtBearerAuthentication
    96.             app.UseJwtBearerAuthentication(new JwtBearerOptions {
    97.                 TokenValidationParameters = new TokenValidationParameters {
    98.                     IssuerSigningKey = TokenAuthOption.Key,
    99.                     ValidAudience = TokenAuthOption.Audience,
    100.                     ValidIssuer = TokenAuthOption.Issuer,
    101.                     ValidateIssuerSigningKey = true,
    102.                     ValidateLifetime = true,
    103.                     ClockSkew = TimeSpan.FromMinutes(0)
    104.                 }
    105.             });
    106.             #endregion
    107.  
    108.             app.UseMvc(routes =>
    109.             {
    110.                 routes.MapRoute(
    111.                     name: "default",
    112.                     template: "{controller=Login}/{action=Index}");
    113.             });
    114.         }
    115.     }
    116. }

  • 在Controllers中新建一个Web API Controller Class，命名为TokenAuthController.cs。我们将在这里完成登录授权

    在同文件下添加两个类，分别用来模拟用户模型，以及用户存储，代码应该是这样

    1. public class User
    2. {
    3.     public Guid ID { get; set; }
    4.     public string Username { get; set; }
    5.     public string Password { get; set; }
    6. }
    7.  
    8. public static class UserStorage
    9. {
    10.     public static List<User> Users { get; set; } = new List<User> {
    11.         new User {ID=Guid.NewGuid(),Username="user1",Password = "user1psd" },
    12.         new User {ID=Guid.NewGuid(),Username="user2",Password = "user2psd" },
    13.         new User {ID=Guid.NewGuid(),Username="user3",Password = "user3psd" }
    14.     };
    15. }

    接下来在TokenAuthController.cs中添加如下方法

    1. private string GenerateToken(User user, DateTime expires)
    2. {
    3.     var handler = new JwtSecurityTokenHandler();
    4.  
    5.     ClaimsIdentity identity = new ClaimsIdentity(
    6.         new GenericIdentity(user.Username, "TokenAuth"),
    7.         new[] {
    8.             new Claim("ID", user.ID.ToString())
    9.         }
    10.     );
    11.  
    12.     var securityToken = handler.CreateToken(new SecurityTokenDescriptor
    13.     {
    14.         Issuer = TokenAuthOption.Issuer,
    15.         Audience = TokenAuthOption.Audience,
    16.         SigningCredentials = TokenAuthOption.SigningCredentials,
    17.         Subject = identity,
    18.         Expires = expires
    19.     });
    20.     return handler.WriteToken(securityToken);
    21. }

    该方法仅仅只是生成一个Auth Token,接下来我们来添加另外一个方法来调用它

    在相同文件中添加如下代码

    1. [HttpPost]
    2. public string GetAuthToken(User user)
    3. {
    4.     var existUser = UserStorage.Users.FirstOrDefault(u => u.Username == user.Username && u.Password == user.Password);
    5.  
    6.     if (existUser != null)
    7.     {
    8.         var requestAt = DateTime.Now;
    9.         var expiresIn = requestAt + TokenAuthOption.ExpiresSpan;
    10.         var token = GenerateToken(existUser, expiresIn);
    11.  
    12.         return JsonConvert.SerializeObject(new {
    13.             stateCode = 1,
    14.             requertAt = requestAt,
    15.             expiresIn = TokenAuthOption.ExpiresSpan.TotalSeconds,
    16.             accessToken = token
    17.         });
    18.     }
    19.     else
    20.     {
    21.         return JsonConvert.SerializeObject(new { stateCode = -1, errors = "Username or password is invalid" });
    22.     }
    23. }

    该文件完整的代码应该是这样

    1. using System;
    2. using System.Collections.Generic;
    3. using System.Linq;
    4. using System.Threading.Tasks;
    5. using Microsoft.AspNetCore.Mvc;
    6. using Newtonsoft.Json;
    7. using System.IdentityModel.Tokens.Jwt;
    8. using System.Security.Claims;
    9. using System.Security.Principal;
    10. using Microsoft.IdentityModel.Tokens;
    11. using CSTokenBaseAuth.Auth;
    12.  
    13. namespace CSTokenBaseAuth.Controllers
    14. {
    15.     [Route("api/[controller]")]
    16.     public class TokenAuthController : Controller
    17.     {
    18.         [HttpPost]
    19.         public string GetAuthToken(User user)
    20.         {
    21.             var existUser = UserStorage.Users.FirstOrDefault(u => u.Username == user.Username && u.Password == user.Password);
    22.  
    23.             if (existUser != null)
    24.             {
    25.                 var requestAt = DateTime.Now;
    26.                 var expiresIn = requestAt + TokenAuthOption.ExpiresSpan;
    27.                 var token = GenerateToken(existUser, expiresIn);
    28.  
    29.                 return JsonConvert.SerializeObject(new {
    30.                     stateCode = 1,
    31.                     requertAt = requestAt,
    32.                     expiresIn = TokenAuthOption.ExpiresSpan.TotalSeconds,
    33.                     accessToken = token
    34.                 });
    35.             }
    36.             else
    37.             {
    38.                 return JsonConvert.SerializeObject(new { stateCode = -1, errors = "Username or password is invalid" });
    39.             }
    40.         }
    41.  
    42.         private string GenerateToken(User user, DateTime expires)
    43.         {
    44.             var handler = new JwtSecurityTokenHandler();
    45.  
    46.             ClaimsIdentity identity = new ClaimsIdentity(
    47.                 new GenericIdentity(user.Username, "TokenAuth"),
    48.                 new[] {
    49.                     new Claim("ID", user.ID.ToString())
    50.                 }
    51.             );
    52.  
    53.             var securityToken = handler.CreateToken(new SecurityTokenDescriptor
    54.             {
    55.                 Issuer = TokenAuthOption.Issuer,
    56.                 Audience = TokenAuthOption.Audience,
    57.                 SigningCredentials = TokenAuthOption.SigningCredentials,
    58.                 Subject = identity,
    59.                 Expires = expires
    60.             });
    61.             return handler.WriteToken(securityToken);
    62.         }
    63.     }
    64.  
    65.     public class User
    66.     {
    67.         public Guid ID { get; set; }
    68.  
    69.         public string Username { get; set; }
    70.  
    71.         public string Password { get; set; }
    72.     }
    73.  
    74.     public static class UserStorage
    75.     {
    76.         public static List<User> Users { get; set; } = new List<User> {
    77.             new User {ID=Guid.NewGuid(),Username="user1",Password = "user1psd" },
    78.             new User {ID=Guid.NewGuid(),Username="user2",Password = "user2psd" },
    79.             new User {ID=Guid.NewGuid(),Username="user3",Password = "user3psd" }
    80.         };
    81.     }
    82. }

  • 接下来我们来完成授权验证部分

    在Controllers中新建一个Web API Controller Class，命名为ValuesController.cs

    在其中添加如下代码

    1. public string Get()
    2. {
    3.     var claimsIdentity = User.Identity as ClaimsIdentity;
    4.  
    5.     var id = claimsIdentity.Claims.FirstOrDefault(c => c.Type == "ID").Value;
    6.  
    7.     return $"Hello! {HttpContext.User.Identity.Name}, your ID is:{id}";
    8. }

    为方法添加装饰属性

    1. [HttpGet]
    2. [Authorize("Bearer")]

    完整的文件代码应该是这样

    1. using System.Linq;
    2. using Microsoft.AspNetCore.Mvc;
    3. using Microsoft.AspNetCore.Authorization;
    4. using System.Security.Claims;
    5.  
    6. namespace CSTokenBaseAuth.Controllers
    7. {
    8.     [Route("api/[controller]")]
    9.     public class ValuesController : Controller
    10.     {
    11.         [HttpGet]
    12.         [Authorize("Bearer")]
    13.         public string Get()
    14.         {
    15.             var claimsIdentity = User.Identity as ClaimsIdentity;
    16.  
    17.             var id = claimsIdentity.Claims.FirstOrDefault(c => c.Type == "ID").Value;
    18.  
    19.             return $"Hello! {HttpContext.User.Identity.Name}, your ID is:{id}";
    20.         }
    21.     }
    22. }

  • 最后让我们来添加视图

    在Controllers中新建一个Web Controller Class，命名为LoginController.cs

    其中的代码应该是这样

    1. using Microsoft.AspNetCore.Mvc;
    2.  
    3. namespace CSTokenBaseAuth.Controllers
    4. {
    5.     [Route("[controller]/[action]")]
    6.     public class LoginController : Controller
    7.     {
    8.         public IActionResult Index()
    9.         {
    10.             return View();
    11.         }
    12.     }
    13. }

    在项目Views目录下新建一个名为Login的目录，并在其中新建一个Index.cshtml文件。

    代码应该是这个样子

    1. <html xmlns="http://www.w3.org/1999/xhtml">
    2. <head>
    3.     <title></title>
    4. </head>
    5. <body>
    6.     <button id="getToken">getToken</button>
    7.     <button id="requestAPI">requestAPI</button>
    8.  
    9.     <script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
    10.     <script>
    11.         $(function () {
    12.             var accessToken = undefined;
    13.  
    14.             $("#getToken").click(function () {
    15.                 $.post(
    16.                     "/api/TokenAuth",
    17.                     { Username: "user1", Password: "user1psd" },
    18.                     function (data) {
    19.                         console.log(data);
    20.                         if (data.stateCode == 1)
    21.                         {
    22.                             accessToken = data.accessToken;
    23.  
    24.                             $.ajaxSetup({
    25.                                 headers: { "Authorization": "Bearer " + accessToken }
    26.                             });
    27.                         }
    28.                     },
    29.                     "json"
    30.                 );
    31.             })
    32.  
    33.             $("#requestAPI").click(function () {
    34.                 $.get("/api/Values", {}, function (data) {
    35.                     alert(data);
    36.                 }, "text");
    37.             })
    38.         })
    39.     </script>
    40. </body>
    41. </html>

最后：完整的代码Sample以及运行手册，请访问：How to achieve a bearer token authentication and authorization in ASP.NET Core

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